Underfeed mechanical stoker



June 2, 1925.

W. J. H. DIPLOCK UNDERFEED MECHANICAL STOKER Filed May 5, 1924 PatentedJune 2, 1925.

"UNITED STATES 7 WILLIAM JOHN HUBER! DI'QPLOCK, or CRQYDON, ENGLAND;ASSIGNOR- or QNET H'ALE To ERITHS ENGINEERING BRITISH COMPANY,

COMPANY; LIMITED, KINGSW A-Y ENG-LAND; A

vnnERrEr-n na omnman s oxaa applic ion filed Mar To all whom 2'6 maycorrec ive: 7

Be it lgnoivn that I, lVnJ n J on y HU- BERT DIPLOC1-Z, a subject of theKing of Great Britain, residing at Ingleside, Barclay Road, Croydon, inthe county of Surrey, England, have invented certain new and usefulImprovements in or Relating to Undert'eed Mechanical Stoker's, of whichthe following is a specification.

This invention relates to mechanical stokers for boiler and otherfurnaces, and refers n'iore particularly to multiple retort underleed'stokers of the kind inWVlli'Ill the fuel is fed into a plurality oftroughs or retorts by means of reciprocz'iting rams, and in whichtuyeres or other air emission means are provided for the admission offorced draught air into the fuel-as it rises from the retorts andspreads over the tops ot'the tuyeres. V

In multiple retort stokersot this character the several troiighs orretorts arefarranged above a main air supply chamber to which fullpressurevair. under the controlof a sin le ClHHlJl is del er d by a fanand overfeed or extension grates are usually provided at the rear endsof the retorts, through which asupplementary supply of air under controland at reduced pressure is admitted to the fuel so that the final stagesof combustion are completed upon the extension grates before the fuel isdischarged, either aijiton'iatically'. or otherwise, over dump plates orother similarly acting devices, to the ashpit.

It has been found in practice that combustion tends to proceed morerapidly at some than at other parts'of the fuel bed, this'unevencombustion being principally due to the fact that the thickness of thefuel bed varies from time to time over different parts of the stoker,"and the air admitted through the tuyeres or other air emission meanstends to take the line of least resistance and accordingly to provide-anexcess of air to the thinnest part of the fuel bed and an insuflicientsupply to the thickest parts and it isthe chief object of the presentinvention to pro-mote even combustion over the entire fuel bed. i

According to one feature of thepresent invention the main air chamber isdivided 7 up by means of partition Walls into smaller chambers, eachchamberbeing provldedvvith 1 2 a-mi ax miea damper by means of which thevolume of a'iir'supplied thereto from the main air duct ortroma commonair chamber. in communication therewith, can be regulated as desired.It, therefore, combustion should take place at a more rapid rate in anyparticular zone of the furnace than in others, or, it any zone notreceivingan adequate supply of air to he moiable to inclined positionsin order toldirect air from thetront compartment directly tothe tuelbedabove the next sue-, ceed'ing compartment Insome instances, itisdesirabletoprovide a supplementary air member beneath the extensiongrate, and when this is done a damper may be provided therefor and maybe located at substantially thesa'me level asthe damper in the partitionwalljust referred to, whereby the air may have a direct ooursefroin thefront compartment to the supplementary chamber beneaththe extensiongrate, 7 The aforesaid improvements may be applied to stokers providedwith variable, strokepushers located withinithe retorts with, or Withoutmoving retort side ivallstor the purpose of advancing and slicing thefuel or to stokers provided with agitating devices and \vith'or Withouts nfaplementary air emission means.

i In order that the invention may be understood and readily carriedintoetfect, the same ivillnovv beexplained more fully ini connectionwith the accompanying draw} ings, inifavhich, i

Figure l isa diagrammatic longitudinal section of a Stoker showing theinvention applied thereto, and V Figure 2 is a transverse section of thesame, taken on the line 4-t of Figure '1.

'teferring to the drawings, the invention is shownapplied more or lessdiagrammatically to a multiple retort under-feed Stoker,

blower, not shoWn.-- An air chamber-is ar-' ranged beneath the retorts Mand tuyeres N, in the present instance, and is divided by a transverselydisposed vertical partition 1-.[ into a front compartment G and a rearcom partment G Air from the duct Gris admitted at the desired pressurethrough a damper I to the compartment G and part of it passes from theconipartment G "at the desired pressure through a damper H 1 to thecompartment G J and J are convenient arrangements of links and levers bywhich the dampersI and H can be adjusted :as re quired.

It will be noted that the partition 11 is disposed adjacent the forwardend of the main air chamber andsubstantially under that portionof theretorts where the fuel bed is usually thicker and humps up due to thefuel feeding mechanism.

It will be obvious that, as shown diagrammatically by the dotted linesin Figure 1, the fuel as it is fed into the stoker humps up and isthicker at the 1 front portion of the fuel bed, above the compartment Gso that in order to penetrate the increased thickness of the fuel atthis'point and promote perfect combustion, air should be supplied at agreater pressure than is required at the lower points of the fuel bedabove the compartment where the fuel bed is thinner. Such adjustment aswillberequired can be readily effected by the arrangement abovedescribed. 7

As is the usual practice in stokers, a supplementary air chamber orcompartment K is provided beneath the extension grates K and a damper Kis provided for regulating the amount of air entering this supplementarychamber. This damper K is shownf as being arranged at substantially thesame level .as the, damper H ,so that when both of these dampers areopen, the current of air from the front compartment G will pass more orless directly to the chamber K 'It will be obvious that instead of asingle transverse partition H two or more partitions disposed atsuitable distances apart and provided with dampers, may be provided soas tojfurther control the supply of air admitted at different points tothe fuel bed;

'while the air instead of passing successively through the severalchambers can, if 'de-.

sired, be conducted fromthesource of air supply through a longitudinallydisposed duct to each of such other chambers.

In lieu of a single damper H as shown,

two or more dampers may also be employed,

while in order to direct the air upwardly into the compartment G acurved deflector plate L may be provided atthe baseof this aircompartment. Shoots, riddling hoppers or other suitable means, notshown, having exit openings may b'e provided to facilitate the removalof any riddlings which may collect at the baseof the compartments (P andG, j Y I lVliat I claim and-desire to secure by Letters Patent of theUnited States is j 1. An underfeed stoker comprising an underfeedretort, an air chamber beneath said retort, tuyer'es located at. thesides of said retort foradmitting air into the fuel as it rises from theretort, a partition wall exbed for dividing the chamber into front andrear compartments, and a damper in said partitionwall' adjacent the topthereof and movable to deflecting positions to direct air from the frontcompartment directly to the fuel bed above the rear compartment. I

2. An underfeed stoker comprising an underfee'd' retort, an air chamberbeneath said retort, tuyere-s located at the sides of said retort, apartition wall extending transversely in the chamber and arrangedbeneath. the forward end of the retort where the fuel bed thickest fordividing the chamber into two con'ipartments, and adamper' hinged at itsloweredge to the upper portion of said partition, said damper beingmovable to in clined positions to direct air from the front compartmentdirectly torthe fuel bed above the compartment beyond the partition.

An underfeed stoker comprising an underfeed retort, an extension grateat the rear end of said retort, a main air chamber beneath said retort,a supplementary air chamberrbeneath said extension grate, tuyereslocated at the sides ofsaid retort for admitting air into the fuel as itrises from the retort, a partition wall extending transversely of saidmain air chamber and dividing the same into two compartments, a damperhinged at its lower edge adjacent the top of said partition wall, and asecond damper for the supplementary air chamber arranged atsubstantially the same level as said first damper.

WILLIAM JOHN HUBERT DIPLOCK.

